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Tuesday, 26 June 2012

Introduction to the Philosophy of Mind III: Non-Cartesian Dualism

Not all Dualists are of the Cartesian variety discussed in the previous post in this series. These Philosophers are known as Non-Cartesian Dualists. One type of Non-Cartesian Dualism is known as a property dualism. Property Dualism only posits one kind of substance but this substance has two distinct properties namely mental and physical properties. One well known example of Non-Cartesian Dualism is Donald Davidson's Anomalous Monism. Davidson's dualism will not be our focus in today's post rather we will focus on another prominent example of Non-Cartesian Dualism.

Lowe's Non-Cartesian DualismE.J Lowe is probably the most influential dualist in philosophy of the mind at the moment, with his form of Non-Cartesian Dualism having made significant impact. Lowe is interested in the identity conditions in cases of strict identity for token items. Let me briefly explain the token/type divide which many readers may not be familiar with. Generally in our common usage of language when we talk about something be identical with something else; we are talking of type identity. Two relatives with a strikingly similar nose may be said to have the same nose, in this instance we are talking in terms of type identity. Token identity differs in that when we say that two things are token identical we really only have one token instance.

Lowe's Non-Cartersian Dualism is interested in how an object can be picked out or individuated. For this purpose Lowe sets out five rules of identity, three uncontroversial and generally accepted and two rules of his own which are intended to clarify the relationship between the mind and body.

Lowe's Rules of Identity

Before any sensible talk can be made about something it must be picked out or individuated. There are two ways of classifying things: i) Classification as individuation (eg. Descartes and Lowe are people) and ii) Classification as characterization where I go on to tell you certain things about various individuated objects (eg. Lowe works in a University department studying the Philosophy of Mind).

Leibniz's Law, this states that if two things which exist at the same time (say A and B), are identical with one another then any properties of A must be properties of B and vice versa.

When we individuate things we make room for re-identifying it. Namely you ascribe particular persistence conditions. To individuate something in a meaningful way you must have some idea of what it is for something to come in and come out of existence.

Lowe's first rule. If two things have token identity (explained earlier) then they must have come into existence at same time and have the same persistence conditions.

Lowe's second rule. You cannot individuate one thing in two different ways but multiple characterizations of a thing can be possible.

For Lowe this laws are meant to show us how it is possible that a person is not necessarily identical with their body but at the same time isn't separable from their body either. One clear example of this is that for Lowe I'm not identical with the mass or composition molecules that make up my body at any one time. As the mass of molecules that make up my body is liable to change over time and we wouldn't want to say I ceased to exist every time my bodily composition changed. According to Lowe a person is metaphysically dependent on their body, so a body is required for person-hood. E.J Lowe thinks that mind and body are distinct substances which happen to share a number of properties (for example person hood or self hood requires the existence of a body).

Non-Cartesian Dualism a more attractive proposition?

It seems clear that a sophisticated Non-Cartesian Dualism, such as the Dualism offered by E.J Lowe and Donald Davidson is certainly superior to the Dualism offered by Descartes. But does this mean that it makes for a more attractive proposition than Cartesian Dualism and I would have to say that such Dualism is still extremely problematic. For example what is often taken to be the real problem for Descartes account namely Mind-Body causation seems to apply equally here and there seems to be no simple way to account for how the mind and body are meant to causally interact.